Using an analytically solvable equilibrium model, we study how the distribution of economic activities is affected by the trade-off between pecuniary externalities, as dependent on transportation costs, and localized technological externalities, as dependent on inter-regional spillovers. We model localized technological externalities as having a cost saving effect that can be interpreted both as a tangible technological advantage, like the presence of a stronger industrial infrastructure, and as an intangible advantage, like a more efficient labour force composition or the presence of some inter-firms knowledge spillover. Under the assumption of capital mobility and labour immobility, we show that whereas decreasing transportation costs, i.e. promoting market openness, leads to sudden agglomeration, increasing inter-regional spillovers, i.e. promoting technological openness, favors a smoother transition between different levels of firms concentration and ultimately leads to a less uneven distribution of welfare.